Article contents
Vortex generation by deep-water breaking waves
Published online by Cambridge University Press: 08 October 2013
Abstract
The connection between wave dissipation by breaking deep-water surface gravity waves and the resulting turbulence and mixing is crucial for an improved understanding of air–sea interaction processes. Starting with the ensemble-averaged Euler equations, governing the evolution of the mean flow, we model the forcing, associated with the breaking-induced Reynolds shear stresses, as a body force describing the bulk scale effects of a breaking deep-water surface gravity wave on the water column. From this, we derive an equation describing the generation of circulation, $\Gamma $, of the ensemble-average velocity field, due to the body force. By examining the relationship between a breaking wave and an impulsively forced fluid, we propose a functional form for the body force, allowing us to build upon the classical work on vortex ring phenomena to both quantify the circulation generated by a breaking wave and describe the vortex structure of the induced motion. Using scaling arguments, we show that
$\Gamma = \alpha {(hk)}^{3/ 2} {c}^{3} / g$, where (
$c, h, k$) represent a characteristic speed, height and wavenumber of the breaking wave, respectively,
$g$ is the acceleration due to gravity and
$\alpha $ is a constant. This then allows us to find a direct relationship between the circulation and the wave energy dissipation rate per unit crest length due to breaking,
${\epsilon }_{l} $. Finally, we compare our model and the available experimental data.
- Type
- Papers
- Information
- Creative Commons
- The online version of this article is published within an Open Access environment subject to the conditions of the Creative Commons Attribution licence .
- Copyright
- ©2013 Cambridge University Press.
References
- 36
- Cited by